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lego/acme/client.go
2018-09-09 12:37:30 +02:00

950 lines
28 KiB
Go

// Package acme implements the ACME protocol for Let's Encrypt and other conforming providers.
package acme
import (
"crypto"
"crypto/x509"
"encoding/base64"
"encoding/pem"
"errors"
"fmt"
"io/ioutil"
"net"
"regexp"
"strconv"
"strings"
"time"
"github.com/xenolf/lego/log"
)
const (
// maxBodySize is the maximum size of body that we will read.
maxBodySize = 1024 * 1024
// overallRequestLimit is the overall number of request per second limited on the
// “new-reg”, “new-authz” and “new-cert” endpoints. From the documentation the
// limitation is 20 requests per second, but using 20 as value doesn't work but 18 do
overallRequestLimit = 18
)
// User interface is to be implemented by users of this library.
// It is used by the client type to get user specific information.
type User interface {
GetEmail() string
GetRegistration() *RegistrationResource
GetPrivateKey() crypto.PrivateKey
}
// Interface for all challenge solvers to implement.
type solver interface {
Solve(challenge challenge, domain string) error
}
// Interface for challenges like dns, where we can set a record in advance for ALL challenges.
// This saves quite a bit of time vs creating the records and solving them serially.
type presolver interface {
PreSolve(challenge challenge, domain string) error
}
// Interface for challenges like dns, where we can solve all the challenges before to delete them.
type cleanup interface {
CleanUp(challenge challenge, domain string) error
}
type validateFunc func(j *jws, domain, uri string, chlng challenge) error
// Client is the user-friendy way to ACME
type Client struct {
directory directory
user User
jws *jws
keyType KeyType
solvers map[Challenge]solver
}
// NewClient creates a new ACME client on behalf of the user. The client will depend on
// the ACME directory located at caDirURL for the rest of its actions. A private
// key of type keyType (see KeyType contants) will be generated when requesting a new
// certificate if one isn't provided.
func NewClient(caDirURL string, user User, keyType KeyType) (*Client, error) {
privKey := user.GetPrivateKey()
if privKey == nil {
return nil, errors.New("private key was nil")
}
var dir directory
if _, err := getJSON(caDirURL, &dir); err != nil {
return nil, fmt.Errorf("get directory at '%s': %v", caDirURL, err)
}
if dir.NewAccountURL == "" {
return nil, errors.New("directory missing new registration URL")
}
if dir.NewOrderURL == "" {
return nil, errors.New("directory missing new order URL")
}
jws := &jws{privKey: privKey, getNonceURL: dir.NewNonceURL}
if reg := user.GetRegistration(); reg != nil {
jws.kid = reg.URI
}
// REVIEW: best possibility?
// Add all available solvers with the right index as per ACME
// spec to this map. Otherwise they won`t be found.
solvers := map[Challenge]solver{
HTTP01: &httpChallenge{jws: jws, validate: validate, provider: &HTTPProviderServer{}},
TLSALPN01: &tlsALPNChallenge{jws: jws, validate: validate, provider: &TLSALPNProviderServer{}},
}
return &Client{directory: dir, user: user, jws: jws, keyType: keyType, solvers: solvers}, nil
}
// SetChallengeProvider specifies a custom provider p that can solve the given challenge type.
func (c *Client) SetChallengeProvider(challenge Challenge, p ChallengeProvider) error {
switch challenge {
case HTTP01:
c.solvers[challenge] = &httpChallenge{jws: c.jws, validate: validate, provider: p}
case DNS01:
c.solvers[challenge] = &dnsChallenge{jws: c.jws, validate: validate, provider: p}
case TLSALPN01:
c.solvers[challenge] = &tlsALPNChallenge{jws: c.jws, validate: validate, provider: p}
default:
return fmt.Errorf("unknown challenge %v", challenge)
}
return nil
}
// SetHTTPAddress specifies a custom interface:port to be used for HTTP based challenges.
// If this option is not used, the default port 80 and all interfaces will be used.
// To only specify a port and no interface use the ":port" notation.
//
// NOTE: This REPLACES any custom HTTP provider previously set by calling
// c.SetChallengeProvider with the default HTTP challenge provider.
func (c *Client) SetHTTPAddress(iface string) error {
host, port, err := net.SplitHostPort(iface)
if err != nil {
return err
}
if chlng, ok := c.solvers[HTTP01]; ok {
chlng.(*httpChallenge).provider = NewHTTPProviderServer(host, port)
}
return nil
}
// SetTLSAddress specifies a custom interface:port to be used for TLS based challenges.
// If this option is not used, the default port 443 and all interfaces will be used.
// To only specify a port and no interface use the ":port" notation.
//
// NOTE: This REPLACES any custom TLS-ALPN provider previously set by calling
// c.SetChallengeProvider with the default TLS-ALPN challenge provider.
func (c *Client) SetTLSAddress(iface string) error {
host, port, err := net.SplitHostPort(iface)
if err != nil {
return err
}
if chlng, ok := c.solvers[TLSALPN01]; ok {
chlng.(*tlsALPNChallenge).provider = NewTLSALPNProviderServer(host, port)
}
return nil
}
// ExcludeChallenges explicitly removes challenges from the pool for solving.
func (c *Client) ExcludeChallenges(challenges []Challenge) {
// Loop through all challenges and delete the requested one if found.
for _, challenge := range challenges {
delete(c.solvers, challenge)
}
}
// GetToSURL returns the current ToS URL from the Directory
func (c *Client) GetToSURL() string {
return c.directory.Meta.TermsOfService
}
// GetExternalAccountRequired returns the External Account Binding requirement of the Directory
func (c *Client) GetExternalAccountRequired() bool {
return c.directory.Meta.ExternalAccountRequired
}
// Register the current account to the ACME server.
func (c *Client) Register(tosAgreed bool) (*RegistrationResource, error) {
if c == nil || c.user == nil {
return nil, errors.New("acme: cannot register a nil client or user")
}
log.Infof("acme: Registering account for %s", c.user.GetEmail())
accMsg := accountMessage{}
if c.user.GetEmail() != "" {
accMsg.Contact = []string{"mailto:" + c.user.GetEmail()}
} else {
accMsg.Contact = []string{}
}
accMsg.TermsOfServiceAgreed = tosAgreed
var serverReg accountMessage
hdr, err := postJSON(c.jws, c.directory.NewAccountURL, accMsg, &serverReg)
if err != nil {
remoteErr, ok := err.(RemoteError)
if ok && remoteErr.StatusCode == 409 {
} else {
return nil, err
}
}
reg := &RegistrationResource{
URI: hdr.Get("Location"),
Body: serverReg,
}
c.jws.kid = reg.URI
return reg, nil
}
// RegisterWithExternalAccountBinding Register the current account to the ACME server.
func (c *Client) RegisterWithExternalAccountBinding(tosAgreed bool, kid string, hmacEncoded string) (*RegistrationResource, error) {
if c == nil || c.user == nil {
return nil, errors.New("acme: cannot register a nil client or user")
}
log.Infof("acme: Registering account (EAB) for %s", c.user.GetEmail())
accMsg := accountMessage{}
if c.user.GetEmail() != "" {
accMsg.Contact = []string{"mailto:" + c.user.GetEmail()}
} else {
accMsg.Contact = []string{}
}
accMsg.TermsOfServiceAgreed = tosAgreed
hmac, err := base64.RawURLEncoding.DecodeString(hmacEncoded)
if err != nil {
return nil, fmt.Errorf("acme: could not decode hmac key: %s", err.Error())
}
eabJWS, err := c.jws.signEABContent(c.directory.NewAccountURL, kid, hmac)
if err != nil {
return nil, fmt.Errorf("acme: error signing eab content: %s", err.Error())
}
eabPayload := eabJWS.FullSerialize()
accMsg.ExternalAccountBinding = []byte(eabPayload)
var serverReg accountMessage
hdr, err := postJSON(c.jws, c.directory.NewAccountURL, accMsg, &serverReg)
if err != nil {
remoteErr, ok := err.(RemoteError)
if ok && remoteErr.StatusCode == 409 {
} else {
return nil, err
}
}
reg := &RegistrationResource{
URI: hdr.Get("Location"),
Body: serverReg,
}
c.jws.kid = reg.URI
return reg, nil
}
// ResolveAccountByKey will attempt to look up an account using the given account key
// and return its registration resource.
func (c *Client) ResolveAccountByKey() (*RegistrationResource, error) {
log.Infof("acme: Trying to resolve account by key")
acc := accountMessage{OnlyReturnExisting: true}
hdr, err := postJSON(c.jws, c.directory.NewAccountURL, acc, nil)
if err != nil {
return nil, err
}
accountLink := hdr.Get("Location")
if accountLink == "" {
return nil, errors.New("Server did not return the account link")
}
var retAccount accountMessage
c.jws.kid = accountLink
_, err = postJSON(c.jws, accountLink, accountMessage{}, &retAccount)
if err != nil {
return nil, err
}
return &RegistrationResource{URI: accountLink, Body: retAccount}, nil
}
// DeleteRegistration deletes the client's user registration from the ACME
// server.
func (c *Client) DeleteRegistration() error {
if c == nil || c.user == nil {
return errors.New("acme: cannot unregister a nil client or user")
}
log.Infof("acme: Deleting account for %s", c.user.GetEmail())
accMsg := accountMessage{
Status: "deactivated",
}
_, err := postJSON(c.jws, c.user.GetRegistration().URI, accMsg, nil)
return err
}
// QueryRegistration runs a POST request on the client's registration and
// returns the result.
//
// This is similar to the Register function, but acting on an existing
// registration link and resource.
func (c *Client) QueryRegistration() (*RegistrationResource, error) {
if c == nil || c.user == nil {
return nil, errors.New("acme: cannot query the registration of a nil client or user")
}
// Log the URL here instead of the email as the email may not be set
log.Infof("acme: Querying account for %s", c.user.GetRegistration().URI)
accMsg := accountMessage{}
var serverReg accountMessage
_, err := postJSON(c.jws, c.user.GetRegistration().URI, accMsg, &serverReg)
if err != nil {
return nil, err
}
reg := &RegistrationResource{Body: serverReg}
// Location: header is not returned so this needs to be populated off of
// existing URI
reg.URI = c.user.GetRegistration().URI
return reg, nil
}
// ObtainCertificateForCSR tries to obtain a certificate matching the CSR passed into it.
// The domains are inferred from the CommonName and SubjectAltNames, if any. The private key
// for this CSR is not required.
// If bundle is true, the []byte contains both the issuer certificate and
// your issued certificate as a bundle.
// This function will never return a partial certificate. If one domain in the list fails,
// the whole certificate will fail.
func (c *Client) ObtainCertificateForCSR(csr x509.CertificateRequest, bundle bool) (*CertificateResource, error) {
// figure out what domains it concerns
// start with the common name
domains := []string{csr.Subject.CommonName}
// loop over the SubjectAltName DNS names
DNSNames:
for _, sanName := range csr.DNSNames {
for _, existingName := range domains {
if existingName == sanName {
// duplicate; skip this name
continue DNSNames
}
}
// name is unique
domains = append(domains, sanName)
}
if bundle {
log.Infof("[%s] acme: Obtaining bundled SAN certificate given a CSR", strings.Join(domains, ", "))
} else {
log.Infof("[%s] acme: Obtaining SAN certificate given a CSR", strings.Join(domains, ", "))
}
order, err := c.createOrderForIdentifiers(domains)
if err != nil {
return nil, err
}
authz, err := c.getAuthzForOrder(order)
if err != nil {
// If any challenge fails, return. Do not generate partial SAN certificates.
/*for _, auth := range authz {
c.disableAuthz(auth)
}*/
return nil, err
}
err = c.solveChallengeForAuthz(authz)
if err != nil {
// If any challenge fails, return. Do not generate partial SAN certificates.
return nil, err
}
log.Infof("[%s] acme: Validations succeeded; requesting certificates", strings.Join(domains, ", "))
failures := make(ObtainError)
cert, err := c.requestCertificateForCsr(order, bundle, csr.Raw, nil)
if err != nil {
for _, chln := range authz {
failures[chln.Identifier.Value] = err
}
}
if cert != nil {
// Add the CSR to the certificate so that it can be used for renewals.
cert.CSR = pemEncode(&csr)
}
// do not return an empty failures map, because
// it would still be a non-nil error value
if len(failures) > 0 {
return cert, failures
}
return cert, nil
}
// ObtainCertificate tries to obtain a single certificate using all domains passed into it.
// The first domain in domains is used for the CommonName field of the certificate, all other
// domains are added using the Subject Alternate Names extension. A new private key is generated
// for every invocation of this function. If you do not want that you can supply your own private key
// in the privKey parameter. If this parameter is non-nil it will be used instead of generating a new one.
// If bundle is true, the []byte contains both the issuer certificate and
// your issued certificate as a bundle.
// This function will never return a partial certificate. If one domain in the list fails,
// the whole certificate will fail.
func (c *Client) ObtainCertificate(domains []string, bundle bool, privKey crypto.PrivateKey, mustStaple bool) (*CertificateResource, error) {
if len(domains) == 0 {
return nil, errors.New("No domains to obtain a certificate for")
}
if bundle {
log.Infof("[%s] acme: Obtaining bundled SAN certificate", strings.Join(domains, ", "))
} else {
log.Infof("[%s] acme: Obtaining SAN certificate", strings.Join(domains, ", "))
}
order, err := c.createOrderForIdentifiers(domains)
if err != nil {
return nil, err
}
authz, err := c.getAuthzForOrder(order)
if err != nil {
// If any challenge fails, return. Do not generate partial SAN certificates.
/*for _, auth := range authz {
c.disableAuthz(auth)
}*/
return nil, err
}
err = c.solveChallengeForAuthz(authz)
if err != nil {
// If any challenge fails, return. Do not generate partial SAN certificates.
return nil, err
}
log.Infof("[%s] acme: Validations succeeded; requesting certificates", strings.Join(domains, ", "))
failures := make(ObtainError)
cert, err := c.requestCertificateForOrder(order, bundle, privKey, mustStaple)
if err != nil {
for _, auth := range authz {
failures[auth.Identifier.Value] = err
}
}
// do not return an empty failures map, because
// it would still be a non-nil error value
if len(failures) > 0 {
return cert, failures
}
return cert, nil
}
// RevokeCertificate takes a PEM encoded certificate or bundle and tries to revoke it at the CA.
func (c *Client) RevokeCertificate(certificate []byte) error {
certificates, err := parsePEMBundle(certificate)
if err != nil {
return err
}
x509Cert := certificates[0]
if x509Cert.IsCA {
return fmt.Errorf("Certificate bundle starts with a CA certificate")
}
encodedCert := base64.URLEncoding.EncodeToString(x509Cert.Raw)
_, err = postJSON(c.jws, c.directory.RevokeCertURL, revokeCertMessage{Certificate: encodedCert}, nil)
return err
}
// RenewCertificate takes a CertificateResource and tries to renew the certificate.
// If the renewal process succeeds, the new certificate will ge returned in a new CertResource.
// Please be aware that this function will return a new certificate in ANY case that is not an error.
// If the server does not provide us with a new cert on a GET request to the CertURL
// this function will start a new-cert flow where a new certificate gets generated.
// If bundle is true, the []byte contains both the issuer certificate and
// your issued certificate as a bundle.
// For private key reuse the PrivateKey property of the passed in CertificateResource should be non-nil.
func (c *Client) RenewCertificate(cert CertificateResource, bundle, mustStaple bool) (*CertificateResource, error) {
// Input certificate is PEM encoded. Decode it here as we may need the decoded
// cert later on in the renewal process. The input may be a bundle or a single certificate.
certificates, err := parsePEMBundle(cert.Certificate)
if err != nil {
return nil, err
}
x509Cert := certificates[0]
if x509Cert.IsCA {
return nil, fmt.Errorf("[%s] Certificate bundle starts with a CA certificate", cert.Domain)
}
// This is just meant to be informal for the user.
timeLeft := x509Cert.NotAfter.Sub(time.Now().UTC())
log.Infof("[%s] acme: Trying renewal with %d hours remaining", cert.Domain, int(timeLeft.Hours()))
// We always need to request a new certificate to renew.
// Start by checking to see if the certificate was based off a CSR, and
// use that if it's defined.
if len(cert.CSR) > 0 {
csr, err := pemDecodeTox509CSR(cert.CSR)
if err != nil {
return nil, err
}
newCert, failures := c.ObtainCertificateForCSR(*csr, bundle)
return newCert, failures
}
var privKey crypto.PrivateKey
if cert.PrivateKey != nil {
privKey, err = parsePEMPrivateKey(cert.PrivateKey)
if err != nil {
return nil, err
}
}
var domains []string
// check for SAN certificate
if len(x509Cert.DNSNames) > 1 {
domains = append(domains, x509Cert.Subject.CommonName)
for _, sanDomain := range x509Cert.DNSNames {
if sanDomain == x509Cert.Subject.CommonName {
continue
}
domains = append(domains, sanDomain)
}
} else {
domains = append(domains, x509Cert.Subject.CommonName)
}
newCert, err := c.ObtainCertificate(domains, bundle, privKey, mustStaple)
return newCert, err
}
func (c *Client) createOrderForIdentifiers(domains []string) (orderResource, error) {
var identifiers []identifier
for _, domain := range domains {
identifiers = append(identifiers, identifier{Type: "dns", Value: domain})
}
order := orderMessage{
Identifiers: identifiers,
}
var response orderMessage
hdr, err := postJSON(c.jws, c.directory.NewOrderURL, order, &response)
if err != nil {
return orderResource{}, err
}
orderRes := orderResource{
URL: hdr.Get("Location"),
Domains: domains,
orderMessage: response,
}
return orderRes, nil
}
// an authz with the solver we have chosen and the index of the challenge associated with it
type selectedAuthSolver struct {
authz authorization
challengeIndex int
solver solver
}
// Looks through the challenge combinations to find a solvable match.
// Then solves the challenges in series and returns.
func (c *Client) solveChallengeForAuthz(authorizations []authorization) error {
failures := make(ObtainError)
authSolvers := []*selectedAuthSolver{}
// loop through the resources, basically through the domains. First pass just selects a solver for each authz.
for _, authz := range authorizations {
if authz.Status == "valid" {
// Boulder might recycle recent validated authz (see issue #267)
log.Infof("[%s] acme: Authorization already valid; skipping challenge", authz.Identifier.Value)
continue
}
if i, solver := c.chooseSolver(authz, authz.Identifier.Value); solver != nil {
authSolvers = append(authSolvers, &selectedAuthSolver{
authz: authz,
challengeIndex: i,
solver: solver,
})
} else {
failures[authz.Identifier.Value] = fmt.Errorf("[%s] acme: Could not determine solvers", authz.Identifier.Value)
}
}
// for all valid presolvers, first submit the challenges so they have max time to propigate
for _, item := range authSolvers {
authz := item.authz
i := item.challengeIndex
if presolver, ok := item.solver.(presolver); ok {
if err := presolver.PreSolve(authz.Challenges[i], authz.Identifier.Value); err != nil {
failures[authz.Identifier.Value] = err
}
}
}
defer func() {
// clean all created TXT records
for _, item := range authSolvers {
if cleanup, ok := item.solver.(cleanup); ok {
if failures[item.authz.Identifier.Value] != nil {
// already failed in previous loop
continue
}
err := cleanup.CleanUp(item.authz.Challenges[item.challengeIndex], item.authz.Identifier.Value)
if err != nil {
log.Warnf("Error cleaning up %s: %v ", item.authz.Identifier.Value, err)
}
}
}
}()
// finally solve all challenges for real
for _, item := range authSolvers {
authz := item.authz
i := item.challengeIndex
if failures[authz.Identifier.Value] != nil {
// already failed in previous loop
continue
}
if err := item.solver.Solve(authz.Challenges[i], authz.Identifier.Value); err != nil {
failures[authz.Identifier.Value] = err
}
}
// be careful not to return an empty failures map, for
// even an empty ObtainError is a non-nil error value
if len(failures) > 0 {
return failures
}
return nil
}
// Checks all challenges from the server in order and returns the first matching solver.
func (c *Client) chooseSolver(auth authorization, domain string) (int, solver) {
for i, challenge := range auth.Challenges {
if solver, ok := c.solvers[Challenge(challenge.Type)]; ok {
return i, solver
}
log.Infof("[%s] acme: Could not find solver for: %s", domain, challenge.Type)
}
return 0, nil
}
// Get the challenges needed to proof our identifier to the ACME server.
func (c *Client) getAuthzForOrder(order orderResource) ([]authorization, error) {
resc, errc := make(chan authorization), make(chan domainError)
delay := time.Second / overallRequestLimit
for _, authzURL := range order.Authorizations {
time.Sleep(delay)
go func(authzURL string) {
var authz authorization
_, err := getJSON(authzURL, &authz)
if err != nil {
errc <- domainError{Domain: authz.Identifier.Value, Error: err}
return
}
resc <- authz
}(authzURL)
}
var responses []authorization
failures := make(ObtainError)
for i := 0; i < len(order.Authorizations); i++ {
select {
case res := <-resc:
responses = append(responses, res)
case err := <-errc:
failures[err.Domain] = err.Error
}
}
logAuthz(order)
close(resc)
close(errc)
// be careful to not return an empty failures map;
// even if empty, they become non-nil error values
if len(failures) > 0 {
return responses, failures
}
return responses, nil
}
func logAuthz(order orderResource) {
for i, auth := range order.Authorizations {
log.Infof("[%s] AuthURL: %s", order.Identifiers[i].Value, auth)
}
}
// cleanAuthz loops through the passed in slice and disables any auths which are not "valid"
func (c *Client) disableAuthz(authURL string) error {
var disabledAuth authorization
_, err := postJSON(c.jws, authURL, deactivateAuthMessage{Status: "deactivated"}, &disabledAuth)
return err
}
func (c *Client) requestCertificateForOrder(order orderResource, bundle bool, privKey crypto.PrivateKey, mustStaple bool) (*CertificateResource, error) {
var err error
if privKey == nil {
privKey, err = generatePrivateKey(c.keyType)
if err != nil {
return nil, err
}
}
// determine certificate name(s) based on the authorization resources
commonName := order.Domains[0]
// ACME draft Section 7.4 "Applying for Certificate Issuance"
// https://tools.ietf.org/html/draft-ietf-acme-acme-12#section-7.4
// says:
// Clients SHOULD NOT make any assumptions about the sort order of
// "identifiers" or "authorizations" elements in the returned order
// object.
san := []string{commonName}
for _, auth := range order.Identifiers {
if auth.Value != commonName {
san = append(san, auth.Value)
}
}
// TODO: should the CSR be customizable?
csr, err := generateCsr(privKey, commonName, san, mustStaple)
if err != nil {
return nil, err
}
return c.requestCertificateForCsr(order, bundle, csr, pemEncode(privKey))
}
func (c *Client) requestCertificateForCsr(order orderResource, bundle bool, csr []byte, privateKeyPem []byte) (*CertificateResource, error) {
commonName := order.Domains[0]
csrString := base64.RawURLEncoding.EncodeToString(csr)
var retOrder orderMessage
_, err := postJSON(c.jws, order.Finalize, csrMessage{Csr: csrString}, &retOrder)
if err != nil {
return nil, err
}
if retOrder.Status == "invalid" {
return nil, err
}
certRes := CertificateResource{
Domain: commonName,
CertURL: retOrder.Certificate,
PrivateKey: privateKeyPem,
}
if retOrder.Status == "valid" {
// if the certificate is available right away, short cut!
ok, err := c.checkCertResponse(retOrder, &certRes, bundle)
if err != nil {
return nil, err
}
if ok {
return &certRes, nil
}
}
stopTimer := time.NewTimer(30 * time.Second)
defer stopTimer.Stop()
retryTick := time.NewTicker(500 * time.Millisecond)
defer retryTick.Stop()
for {
select {
case <-stopTimer.C:
return nil, errors.New("certificate polling timed out")
case <-retryTick.C:
_, err := getJSON(order.URL, &retOrder)
if err != nil {
return nil, err
}
done, err := c.checkCertResponse(retOrder, &certRes, bundle)
if err != nil {
return nil, err
}
if done {
return &certRes, nil
}
}
}
}
// checkCertResponse checks to see if the certificate is ready and a link is contained in the
// response. if so, loads it into certRes and returns true. If the cert
// is not yet ready, it returns false. The certRes input
// should already have the Domain (common name) field populated. If bundle is
// true, the certificate will be bundled with the issuer's cert.
func (c *Client) checkCertResponse(order orderMessage, certRes *CertificateResource, bundle bool) (bool, error) {
switch order.Status {
case "valid":
resp, err := httpGet(order.Certificate)
if err != nil {
return false, err
}
cert, err := ioutil.ReadAll(limitReader(resp.Body, maxBodySize))
if err != nil {
return false, err
}
// The issuer certificate link may be supplied via an "up" link
// in the response headers of a new certificate. See
// https://tools.ietf.org/html/draft-ietf-acme-acme-12#section-7.4.2
links := parseLinks(resp.Header["Link"])
if link, ok := links["up"]; ok {
issuerCert, err := c.getIssuerCertificate(link)
if err != nil {
// If we fail to acquire the issuer cert, return the issued certificate - do not fail.
log.Warnf("[%s] acme: Could not bundle issuer certificate: %v", certRes.Domain, err)
} else {
issuerCert = pemEncode(derCertificateBytes(issuerCert))
// If bundle is true, we want to return a certificate bundle.
// To do this, we append the issuer cert to the issued cert.
if bundle {
cert = append(cert, issuerCert...)
}
certRes.IssuerCertificate = issuerCert
}
} else {
// Get issuerCert from bundled response from Let's Encrypt
// See https://community.letsencrypt.org/t/acme-v2-no-up-link-in-response/64962
_, rest := pem.Decode(cert)
if rest != nil {
certRes.IssuerCertificate = rest
}
}
certRes.Certificate = cert
certRes.CertURL = order.Certificate
certRes.CertStableURL = order.Certificate
log.Infof("[%s] Server responded with a certificate.", certRes.Domain)
return true, nil
case "processing":
return false, nil
case "invalid":
return false, errors.New("order has invalid state: invalid")
default:
return false, nil
}
}
// getIssuerCertificate requests the issuer certificate
func (c *Client) getIssuerCertificate(url string) ([]byte, error) {
log.Infof("acme: Requesting issuer cert from %s", url)
resp, err := httpGet(url)
if err != nil {
return nil, err
}
defer resp.Body.Close()
issuerBytes, err := ioutil.ReadAll(limitReader(resp.Body, maxBodySize))
if err != nil {
return nil, err
}
_, err = x509.ParseCertificate(issuerBytes)
if err != nil {
return nil, err
}
return issuerBytes, err
}
func parseLinks(links []string) map[string]string {
aBrkt := regexp.MustCompile("[<>]")
slver := regexp.MustCompile("(.+) *= *\"(.+)\"")
linkMap := make(map[string]string)
for _, link := range links {
link = aBrkt.ReplaceAllString(link, "")
parts := strings.Split(link, ";")
matches := slver.FindStringSubmatch(parts[1])
if len(matches) > 0 {
linkMap[matches[2]] = parts[0]
}
}
return linkMap
}
// validate makes the ACME server start validating a
// challenge response, only returning once it is done.
func validate(j *jws, domain, uri string, c challenge) error {
var chlng challenge
hdr, err := postJSON(j, uri, c, &chlng)
if err != nil {
return err
}
// After the path is sent, the ACME server will access our server.
// Repeatedly check the server for an updated status on our request.
for {
switch chlng.Status {
case "valid":
log.Infof("[%s] The server validated our request", domain)
return nil
case "pending":
case "processing":
case "invalid":
return handleChallengeError(chlng)
default:
return errors.New("the server returned an unexpected state")
}
ra, err := strconv.Atoi(hdr.Get("Retry-After"))
if err != nil {
// The ACME server MUST return a Retry-After.
// If it doesn't, we'll just poll hard.
ra = 5
}
time.Sleep(time.Duration(ra) * time.Second)
hdr, err = getJSON(uri, &chlng)
if err != nil {
return err
}
}
}